1. Field of the Invention
The present invention relates to an image forming apparatus capable of controlling printing interruption, a method of controlling the same, and a storage medium.
2. Description of the Related Art
In general, the price of an image forming apparatus, such as a copying machine or a printer, has been progressively reduced, and therefore demand for price reduction of a controller for controlling a printer has been increasing.
Further, printers configured to print out an image based on print data received from a host computer include a host-based type that employs, with a view to cost reduction, a printing method in which a host computer rasterizes print data into a format which can be output by the printer, and then delivers the rasterized data to the printer.
As such printers described above, with a tendency toward reduction of apparatus size and price, there has appeared a type which is configured to dispense with a cooling unit, such as a fan. Further, some printers of this type are provided with a temperature rise control mode in which a predetermined cooling time is provided when the printer internal temperature has risen, thereby disabling a printing operation until the printer internal temperature falls.
Further, there has conventionally been proposed a printer that employs an image printing control method in which the remaining amount of toner is constantly monitored and when the amount of used toner exceeds a predetermined threshold value, the mode of printing is switched to an economy mode (see Japanese Patent Laid-Open Publication No. 2006-284794).
In the field of small-sized printers, development of a printer without a cooling unit, such as a fan, has been proceeding so as to achieve reduction of apparatus size and costs.
In such a printer having no cooling unit, however, when a printing operation is started, the printer internal temperature rises in a short time, and hence the printer frequently shifts to the temperature rise control mode, resulting in frequent interruption of the printing operation.
Further, in a small-sized printer, since the amount of toner that can be contained in a small-sized cartridge is limited, interruption of a printing operation due to shortage of toner frequently occurs. In addition, in the small-sized printer, when toner runs out, it is required to replace a toner cartridge with a new one, which causes long-time suspension of a printing operation.
In such a small-sized printer provided with the temperature rise control mode and loaded with a small-sized cartridge, such an operation process is followed as illustrated, by way of example, in a timing diagram in FIG. 6 which shows printing time in continuous printing. In the operation process illustrated in FIG. 6, when printing is started in a printer, the printer internal temperature rises and the printer shifts to the temperature rise control mode after printing of several tens of sheets. As a consequence, the printing operation is suspended until the printer internal temperature falls.
Even after the printer internal temperature falls and the printer shifts from the temperature rise control mode, if toner runs out after printing of several sheets, the operation process has to shift to cartridge replacement, and therefore it inevitably takes a long time before completion of the printing.
Particularly in a color printer, since toner cartridges corresponding in number to colors in use exist in the printer, shift to the temperature rise control mode and cartridge replacement frequently take place, and therefore it often occurs that a user has to wait for a long time before completion of printing.